Violence Reduction in Joliet, Illinois: An Evaluation of the Strategic Tactical Deployment Program

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Evidence-Based Policing   

 

Evidence-based policing is the use of the best available research to guide police practice 

(Sherman, 1998). Evidence-based policing traces its origin to the medical profession where 

practice based in research is routinely used to treat patients. In the early 1990s clinicians at 

McMaster’s University began using the term “evidence-based medicine” to define the systemic 

use of published research as the basis of clinical decision making (Claridge and Fabian, 2005).  

Noted criminologist Lawrence Sherman (1998) proposed that the concept of evidence-based 

research be applied to policing arguing that policing should be more like medicine. Sherman 

(1998) defined evidence-based policing as using “the best available research on the outcomes of 

police work to implement guidelines and evaluate agencies, units, and officers.”  

 

Traditionally, police work has been guided by the experience of the officers and not 

empirical evaluation. How a police officer acted in a specific situation was largely based on 

previous experience or the experiences of other police officers. Police believed that experience 

was the best teacher and that it gave them superior judgment (Sherman, 1984). Every situation 

was unique and, as a result, practices could not be generalized even if there was scientific 

evidence to support them. Experience taught lessons to police officers that they considered 

crucial to effective performance and career longevity (Bayley and Bitter, 1984).  

 

Dempsey and Frost (2008) argue that police departments have traditionally been unwilling 

to deviate from “the way we’ve always done things mentality.” In fact, Sherman (1984) argued 

that some police officers suffer from the “funnel effect” of experience. As time passes, they have 

less and less knowledge about how their actions affected a situation because of their reliance on 

past experience. Nevertheless, police have continued to allow experience to shape their goals, 

tactics, and presence (Bayley and Bitter, 1984). As a result, police practices remain untested. 

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Criminal justice decision making has been based on anecdotes, media attention, and political 

pressure (Sherman, 1998). Evidence-based policing shifts the focus of criminal justice decision 

making to the assessment of police practices through the collection of data, scientific analysis, 

and the creation of measureable outcomes.  

 

Experience not only set the standard for police practice for many years, but was also 

believed to be better than empirical research. In fact, Hubert Williams (2010), writing for the 

Police Foundation, reports that it was a common view among police administrators and managers 

that they, like doctors, engineers, and lawyers, were the experts in the field of public safety. The 

boots on the ground, who put their lives on the line every day to protect the public were the 

experts; and they neither required nor desired outsiders who knew little, if anything, about their 

work to tell them how to do their jobs. Police officials were not only skeptical of outside 

involvement, but were also resentful of academics who they believed wanted to obtain police 

data and information for research purposes in order to promote themselves as experts in a field 

they knew little about.  

 

While most police departments continued to hold experience in high regard, in the 1970s 

some police departments began participating in experimental research as a direct result of the 

influence of the Police Foundation (Williams 2010). The introduction of experimental research 

into policing by the Police Foundation was a major factor in breaking down the barriers between 

research and policing. It also opened the door for criminologists to become actively involved in 

empirical research. Three research experiments, sponsored by the Police Foundation, pushed 

research and ultimately evidence-based policing into the forefront: the Kansas City Preventive 

Patrol Experiment, the Newark Foot Patrol Experiment, and the Newark Fear Reduction Study.   

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All three of the above studies demonstrated the importance of research in policing. Kansas 

City and Newark opened their doors to research when experience was considered the best 

indicator of police effectiveness. These police departments helped to change policing from an 

institution known for being conservative and resistance to change, to suddenly standing out as 

the leader in criminal justice innovation (Weisburd and Eck, 2004:43). Even though each of 

these studies was unique, the overarching message from them is that police practices should be 

based on scientific evidence about what works best (Williams, 2010). As the number of 

challenges faced by the police increase, the demand for cost-efficient ways to achieve the goals 

of the police mission also increase. These studies show that the best way to establish cost-

efficient methods is to base practice on empirical research. Evidence-based policing provides 

police departments with a level of expertise that is not achievable by basing practice solely on 

experience.  

 

In spite of all the attention given to evidence-based policing, it is not without its critics. 

Sherman (1998) argues that problem-oriented policing is the basis of evidence-based policing. 

Those solutions that work become evidence-based practices. Bullock and Tilley (2009), 

however, argue that problem-oriented policing, in spite of its popularity in academic circles, has 

had little success. This position is supported by Herman Goldstein (2003), the father of police-

problem solving, who wrote that “there was no discernible, sustained, consistent effort within 

policing to make the basic premise that ‘knowledge informs practice’ a routine part of policing.”  

While police may be slow to adapt evidence-based practices, and some doubt the success of 

problem-oriented policing, Goldstein’s (1990) seminal work and its link to community policing 

have led to numerous examples of police developing nontraditional responses to police problems 

including the highly touted Boston Gun Project, which focused on reducing youth violence by 

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